Question

Describe the effects of excessive hemorrhage on the antidiuretic system and on the renin-angiotensin-aldosterone system.  Be sure to explain how these systems help to keep your blood pressure from going too low.

Answer 1

Excessive hamorrhage will lead to decrased Blood pressure.

This will lead to decrease in blood supply to kidney.

Decrease blood flow to kindey -----> Decresed filterate across Glomerular capillary ----> Decresed sodium ion concentration reaching DCT -------> Sensed by the macula densa cells of DCT ------> stimulation of Juxtaglomerular cells in the afferent arteriole -----> secrete Renin ----> angiotensinogen from liver -----> Angiotensin I -----> in lungs by Angiotensin converting enzyme ----+> Angiotensin II ------> Increases aldosterone release from adrenal gland.

Mainatance of BP

1) Angiotensin II is a potent vasoconstrictor and hence constricts the arteries and hence tries to normalise BP.

2) Increased aldosterone leads to increased salt and water retention. Hence maintain the fluid balance and hence the blood pressure